Vehicles for maintaining railroad tracks including the rail portions of the tracks and the railroad ties supporting the rails are known in the prior art and have been in use since the inception of the railroad industry. The problems in maintaining these components of the tracks were recognized early, and various attempts have been made to provide devices which facilitate repairs or refurbishment including the replacement of deteriorated rail supporting ties. In replacing ties, the operation is facilitated if the downward pressure exerted on them by the rail portions is eliminated by raising the track first. Structures for accomplishing this function are also known in the art, and U.S. Pat. No. 3,604,358 issued to Franz Plasser et al is one fairly recent illustration of a device designed to accomplish this function. The structure of that reference accomplishes raising of the rails by use of an extension vehicle which runs over the ground. The rails are diverted up over this extension vehicle so that, as the vehicle is moved, that portion of the track for which ties are being replaced is elevated and the ties thereunder are more accessible.
One drawback of this structure is that the rails are brought into sliding engagement with the extension vehicle. As a result, damage can be inflicted upon the rails or, at a minimum, some measure of abrasion will be applied to the rail surfaces as they slide across portions of the extension vehicle.
There are other problems existent with structures known in the prior art. Frequently, the vehicle used for effecting repairs and tie replacement is normally configured for movement over roads, but having special mounting apparatus to position the vehicle on a railroad track when the repair and tie replacement is to be effected. When, however, the vehicle is to be positioned on a length of track for work thereon, means must be provided for stabilizing the vehicle during its operation. Many structures utilize hydraulic or pneumatic lifters to elevate the wheels mounting the vehicle to a height above the tracks. It is desirable that these lifters be spaced apart laterally at a substantial distance to increase the base area of the vehicle and, in turn, the stability. It is essential to safe operation of the vehicle that these lifters be spaced apart far enough so that ground engaging portions of the lifters will be straddling the ties. If the ground engaging portions rested on the ties, stability might be sacrificed since the ground engaging portions might slide off of the irregular surface created by the ties.
The fact that these stabilizers need be spaced at a minimum distance somewhat greater than the length of the tie creates problems when the vehicle is being operated on a road or highway. State legislation frequently provides that any load being transported must not exceed a maximum width, and, even when this maximum width is not exceeded, special equipment must be used to warn that the width of the load exceeds a second width corresponding to the normal width of an automobile or similar vehicle.
One other problem which has remained uncured by the various devices designed to accomplish the railway maintenance function relates to the actual removal of the ties from beneath the elevated rails. Many of these structures utilize a hydraulically actuated boom for pushing the ties from their positions in the railway bed. This pushing function is accomplished by use of an arm having a single tine. The arm is brought to bear against the tie so that the tine digs into the wood of which the tie is made. The arm is then moved to push the tie from its location in the bed. Frequently, however, the force exerted by the arm will not be applied along the axis of the tie, and the tie will rotate about the pivot point provided by the single tine. A smooth and complete displacement from its location on the bed can, thereby, be hindered.
It is these problems existent in the prior art to which the invention of this application is directed. The invention provides an improved railway maintenance machine to solve these problems.